This set of Q&A focuses more on the design process for Web applications and especially on working with visual hierarchy. Some excerpts:

"Too often, everything on a Web page looks the same and users don’t know where to start. Conversely, everything looks very different and users end up bouncing between elements that are competing for their attention. An effective hierarchy employs just enough meaningful differentiation to walk users through the unique content and actions on a page in a purposeful order."

"The process of removing what isn’t needed helps the important stuff get seen. Edward Tufte refers to visual noise as “chart junk.” Anything that isn’t adding value is taking away from it. So I’d say be wary of too many visual elements and look for the fewest possible “words” to communicate what you need."